电场作用条件与作物种子生长的相关性

在综合评价电场强度及处理时间对作物生物效应影响时, 如何确定生物效应指标之间的权重一直是困扰生物信息综合评价的核心问题。比如叶绿素增长1 mg·L^–1 的价值相当于多少厘米根长的增加, 这是一个难以回答的问题。同时, 通过指标加权合成的方法获得综合评价的结果也存在信息丢失的缺陷。针对电场条件对作物生物效应的影响, 利用数据包络分析的基本思想, 给出了用于综合评价电场强度及处理时间对作物生物效应影响的非参数综合分析方法和相应的数学模型, 该方法不仅可以克服上述缺点, 而且还为分析不同外部条件对作物综合生物效应的影响程度提供了一种有效的分析工具。应用该方法综合评价了不同电场强度和不同处理时间对小麦 (Triticum aestivum)种子幼苗株高和根长的影响。结果表明: 不同电场强度和处理时间对小麦幼苗生长产生不同影响, 在0.5–6.0 kV·cm^–1场强范围内, 随电场强度增加, 生理指标呈现振荡性变化, 当处理时间为5分钟时, 1.0和2.0 kV·cm^–1场强为最佳处理条件; 处理时间为10分钟时, 2.5 kV·cm^–1场强为最佳处理条件。     

Effects of chicken intestinal antimicrobial peptides on humoral immunity of chickens and antibody titres after vaccination with infectious bursal disease virus vaccine in chicken

Sixty chickens were randomly divided into two groups (30 chickens in each group) to determine the effect of oral administration of chicken intestinal antimicrobial peptides (CIAMP) on the humoral immune response. Chickens of both groups were fed the same diet. In the treatment group chickens received drinking water supplemented with CIAMP (1 microg/ml) right after hatching. Samples of blood, bursa of Fabricus, spleen and intestine were taken at day 1, 4, 7, 10 and 17 of experiment. CIAMP supplementation enhanced the content of IgG and IgM in serum from day 4-10 and day 10-17, respectively, (p < 0.05), IgM-forming cells in bursa of Fabricus and spleen at the age of 7 days (p < 0.05) and IgG-forming cells in bursa of Fabricus at the age of 4 days (p < 0.05). In addition, CIAMP enhanced the IgA-forming cells in caecal tonsils diffuse area at day 4 (p < 0.05). Furthermore, CIAMP enhanced the antibody response to infectious bursal disease virus vaccine (IBDV) in chickens 21 days following IBDV vaccine administration (p < 0.05). These results suggested that CIAMP could modulate the humoral immune response of chickens and increased the antibody titres of infectious bursal disease virus vaccine.     

QuikChange shuffling: a convenient and robust method for site-directed mutagenesis and random recombination of homologous genes

Here we describe a robust method, termed QuikChange shuffling, for efficient site-directed mutagenesis and random recombination of homologous genes. The homologous genes are fragmented, and the random fragments are reassembled in a self-priming polymerase reaction to obtain chimeric genes. The product is then mixed with linearized vector and two pairs of complementary mutagenic primers, followed by assembly of the chimeric genes and linearized vector through QuikChange-like amplification to introduce recombinant plasmids with a site-directed mutation. The method, which can yield 100% chimeric genes after library construction, is more convenient and efficient than current DNA shuffling methods.     

丝状真菌Amorphotheca resinae ZN1的糠醛降解代谢分析

木质纤维素在预处理过程产生的降解产物对后续的酶水解和微生物发酵过程产生了强烈的抑制。因此,这些抑制物的脱除即所谓的"脱毒"步骤是正常进行后续酶解和发酵的前提条件。我们对本实验室筛选的丝状真菌Amorphotheca resinae ZN1的糠醛的代谢路径进行了研究。丝状真菌A.resinae ZN1转化糠醛的降解代谢途径可以简述为:糠醛首先快速地转化为毒性较低的糠醇;在有氧条件下,糠醇又再度生成不致对微生物产生危害的低浓度糠醛,糠醛继续氧化为糠酸。推测糠酸可能继续进入TCA循环,进而完成糠醛的完全降解。研究结果为将来加快丝状真菌A.resinae ZN1生物脱毒速率、改善木质纤维素生物转化的限速步骤提供了重要的实验依据。     

Identification of Chromosomes from Multiple Rice Genomes Using a Universal Molecular Cytogenetic Marker System

To develop reliable techniques for chromosome identification is critical for cytogenetic research, especially for genomes with a large number and smaller-sized chromosomes. An efficient approach using bacterial artificial chromosome （BAC） clones as molecular cytological markers has been developed for many organisms. Herein, we present a set of chromosomal arm-specific molecular cytological markers derived from the gene-enriched regions of the sequenced rice genome. All these markers are able to generate very strong signals on the pachytene chromosomes of Oryza sativa L. （AA genome） when used as fluorescence in situ hybridization （FISH） probes. We further probed those markers to the pachytene chromosomes of O. punctata （BB genome） and O. officinalis （CC genome） and also got very strong signals on the relevant pachytene chromosomes. The signal position of each marker on the related chromosomes from the three different rice genomes was pretty much stable, which enabled us to identify different chromosomes among various rice genomes. We also constructed the karyotype for both O. punctata and O. officinalis with the BB and CC genomes, respectively, by analysis of 10 pachytene cells anchored by these chromosomal arm-specific markers.     

Novel aminopeptidase N inhibitors derived from antineoplaston AS2–5 (Part I)

Overexpression of zinc-dependent metalloproteinase, aminopeptidase N (APN/CD13), is considered to be involved in the process of tumor invasion and metastasis. Herein we describe the synthesis and in vitro enzymatic inhibition assay of antineoplaston AS2–5 scaffold peptidomimetic compounds. The results demonstrated that most of these l-iso-glutamine derivatives displayed selective inhibitory activity against APN as compared with MMP-2, with IC₅₀ values in the micromole range. The structure–activity relationships were also briefly discussed.     

Delayed development of the whitefly (Bemisia tabaci) and increased parasitism by Encarsia bimaculata in response to sublethal doses of piperonyl butoxide

Abstract Effects of sublethal piperonyl butoxide (PB) on parasitization of Bemisia tabaci (Gennadius ) (Hemiptera: Aleyrodidae) by Encarsia bimaculata Heraty et Polaszek (Hymenoptera: Aphelinidae) were evaluated both in cage and greenhouse experiments. When first, second and third instar B. tabaci nymphs were treated with PB, all but the first instar were significantly prolonged. Data indicated that sublethal PB could improve E. bimaculata parasitism rates without influencing parasitoid eclosion rates. Prolonged development increased rates of parasitism by E. bimaculata, from 17.6% to 24.7% in cages, presumably by increasing the duration of host exposure. Sublethal PB combined with E. bimaculata as an integrated approach to control B. tabaci was evaluated using life table parameters under greenhouse conditions. Indices of population trend (I) calculated from life tables were estimated at 4.6 for B. tabaci exposed to PB and parasitoids compared to 14.1 with parasitoids alone and 23.5 in untreated controls. The results showed that after PB was sprayed and parasitoids introduced, development of B. tabaci was delayed and the peak of each stage was postponed. The older nymphal stage had highest mortality, primarily due to mortality caused by parasitism by E. bimaculata.     

郫县豆瓣发酵过程的微生物多样性及溯源分析

[目的] 解析郫县豆瓣及其酿造半成品-蚕豆醅与辣椒醅微生物多样性和来源,探究郫县豆瓣酿造过程风味化合物特征。[方法] 采用高通量测序法测定蚕豆醅、辣椒醅与混合醅（蚕豆醅-辣椒醅混合物,发酵成熟形成郫县豆瓣）在酿造过程中的微生物群落结构;利用高效气相质谱与高效液相色谱高通量检测蚕豆醅及辣椒醅中基础理化指标及挥发性、非挥发性风味化合物浓度;利用多种生物信息学分析方法对混合醅酿造微生物及风味化合物进行溯源。[结果] 微生物方面：44%–59%的混合醅细菌来源于辣椒醅,5%–22%的混合醅细菌来源于蚕豆醅,其他混合醅细菌来源未知。同时,42%–77%的混合醅真菌来源于辣椒醅,2%–18%的混合醅真菌来源于蚕豆醅,其他混合醅真菌来源未知。另外,16个细菌属由辣椒醅特异性贡献;2个细菌属及2个真菌属由蚕豆醅特异性贡献。化合物方面：1-辛烯-3醇（1-octen-3-ol）、苯乙醛（phenylacetaldehyde）、异丁醛（isobutyraldehyde）、苹果酸（malic acid）与糠醛（furfural）仅由蚕豆醅贡献。辣椒素（capsaicin）、3-甲基-1-丁醇（3-methyl-1-butanol）、已醇（hexanol）与异丁醇（isobutanol）仅由辣椒醅贡献。[结论] 郫县豆瓣发酵中大部分微生物来源于辣椒醅,大部分发酵底物（氨基酸及葡萄糖）来源于蚕豆醅。两种发酵半成品均特异性贡献微生物及风味化合物,形成郫县豆瓣的独特风味密码。     

Bayesian Network Analysis Reveals Alterations to Default Mode Network Connectivity in Individuals at Risk for Alzheimer's Disease

Alzheimer''s disease (AD) is associated with abnormal functioning of the default mode network (DMN). Functional connectivity (FC) changes to the DMN have been found in patients with amnestic mild cognitive impairment (aMCI), which is the prodromal stage of AD. However, whether or not aMCI also alters the effective connectivity (EC) of the DMN remains unknown. We employed a combined group independent component analysis (ICA) and Bayesian network (BN) learning approach to resting-state functional MRI (fMRI) data from 17 aMCI patients and 17 controls, in order to establish the EC pattern of DMN, and to evaluate changes occurring in aMCI. BN analysis demonstrated heterogeneous regional convergence degree across DMN regions, which were organized into two closely interacting subsystems. Compared to controls, the aMCI group showed altered directed connectivity weights between DMN regions in the fronto-parietal, temporo-frontal, and temporo-parietal pathways. The aMCI group also exhibited altered regional convergence degree in the right inferior parietal lobule. Moreover, we found EC changes in DMN regions in aMCI were correlated with regional FC levels, and the connectivity metrics were associated with patients'' cognitive performance. This study provides novel sights into our understanding of the functional architecture of the DMN and adds to a growing body of work demonstrating the importance of the DMN as a mechanism of aMCI.